Microwave cooking has experienced substantial growth due to the convenience and time savings associated with microwave cooking. However, often consumers are dissatisfied with food cooked in microwave ovens since they often lack many of the characteristics associated with a particular food cooked in a conventional oven. In particular, often the exterior surfaces of a food cooked by microwave energy is soggy or lacks the desired degree of browning or crispness. Various attempts have been made to provide microwave cooked-in food packages which are adapted to provide browning, however none of these attempts have provided an entirely satisfactory package which is usable for shipping, selling, storing and serving of a packaged food.
One approach, as disclosed in Brastad U.S. Pat. No. 4,267,420 and Brastad et al. U.S. Pat. No. 4,230,924 , utilizes flexible sheets of microwave interactive materials wrapped closely about individual items of food so that the interactive material converts at least a portion of the impinging microwave energy into heat which can brown the food surface. However, flexible dielectric wrapping materials can have leakage and/or venting problems for foods having fluid such as grease or vapor driven out of the food during heating, such as breakfast sausages. In addition, the consumer may find it cumbersome to remove sheets from individual food items, particularly where the food items are hot after cooking. Flexible wrapping sheets are also not suitable for shipping or display, and therefore an additional outer carton is required.
Goldsuse U.S. Pat. No. 3,591,751 discloses a microwave cooking implement in which both the top and bottom surfaces of a food article are in contact with means for converting microwave energy into heat for browning the food. The upper browning means includes a plurality of metal rods which are gravity biased into contact with the food, however incorporating bulky metal rods into an outer carton would be difficult and costly.
In another approach, as disclosed in Tobelmann et al. U.S. Pat. No. 4,777,053 upper and lower heating elements are secured to the inner surface of a carton so as to contact the surface of a food article contained therein to provide browning. However, the heating panels are fixed to the upper and lower surfaces of the carton and thus when the food shrinks during cooking, the heating panels lose contact with the food surface and the browning effect is diminished.
Maroszek U.S. Pat. No. 4,594,492 discloses a resiliently biased browning insert for a microwave package in which a pair of flanges are provided on a panel having a microwave interactive layer for browning thereon. The flanges are folded back such that when the insert is placed inside a microwave package, the folded-back flanges bias the panel having the microwave interactive layer thereon toward the food product. Thus, the flanges or wing sections press against the upper portion of the carton to resiliently bias the interactive portions into contact with the food surface. However, since the flanges are biased from the central section having the microwave interactive layer thereon, it is difficult to properly place the insert within the carton while insuring the flanges are properly folded in the biased condition and providing contact with the food product. In addition, the microwave heating insert has a tendency to curl during heating which will reduce contact of the insert with the food articles, diminishing the browning ability of the insert. Moreover, due to the weight of the food product, the biasing effect may be reduced due to repeated bending of the bias flaps as where the container is turned over or shaken during handling. This may cause fatigue in the bias which can reduce the effectiveness in maintaining the browning layer in contact with the food surface.